Effect of trans-Cinnamaldehyde-Loaded ZIF‑8 Nanoparticles against Escherichia coli MG1655 Adhered to Stainless-Steel, Polyurethane, and Latex Surfaces.

This study evaluated the effectiveness of trans-cinnamaldehyde-entrapped Zeolitic Imidazole Framework-8 (ZIF-8) (TC@ZIF-8) nanoparticles in removing biofilms of Escherichia coli MG1655 adhered to common food-contact surfaces. trans-Cinnamaldehyde (TC) release was tested at room temperature using a phosphate-buffered saline (PBS): methanol (5%) mixture and UV-visible spectrophotometry at 295 nm. 1 cm × 1 cm coupons made from stainless steel, polyurethane sheet, and latex were characterized in terms of surface free energy and contact angles. The surface morphology of the different coupons was analyzed using scanning electron microscopy (SEM). Antibacterial activity was assessed by determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The ability of the 0.5TC@ZIF-8 nanoparticles to prevent the growth of E. coli MG1655 colonies on the coupons and to remove already established E. coli MG1655 biofilms was evaluated at different MBC concentrations. A 2×MBC concentration prevented bacterial attachment on stainless steel and latex surfaces. In contrast, a 20×MBC concentration with 24 h contact time was required to remove already established biofilms from the stainless-steel surface. The same treatment yielded a 1.88-log and a 3.38-log reduction on polyurethane and latex surfaces, respectively.